#45574 [SC-Insight] Redundant Per‑Item Upper Bound Check in `validateLiquidationFactors`

Submitted on May 17th 2025 at 07:43:47 UTC by @chista0x for Audit Comp | Flare | FAssets

• Report ID: #45574

• Report Type: Smart Contract

• Report severity: Insight

• Target: https://github.com/flare-foundation/fassets/blob/main/contracts/assetManager/library/SettingsValidators.sol

• Impacts:

Description

Brief/Introduction

In the validateLiquidationFactors function of SettingsValidators.sol, the per-item requirement

require(liquidationFactors[i] > SafePct.MAX_BIPS, "factor not above 1");

is executed inside the loop for every index. However, because the loop already enforces a strictly increasing sequence (liquidationFactors[i] > liquidationFactors[i – 1]), it suffices to check the first element against SafePct.MAX_BIPS and infer the rest will also satisfy it. Moving that check outside the loop reduces gas costs by eliminating a redundant comparison on every iteration.

Optimization Details

Current loop logic:

for (uint256 i = 0; i < liquidationFactors.length; i++) {
    require(liquidationFactors[i] > SafePct.MAX_BIPS, "factor not above 1");
    require(vaultCollateralFactors[i] <= liquidationFactors[i], "vault collateral factor higher than total");
    require(i == 0 || liquidationFactors[i] > liquidationFactors[i - 1], "factors not increasing");
}

• Redundancy: After verifying liquidationFactors[0] > MAX_BIPS, the monotonic increase check guarantees

  liquidationFactors[1] > liquidationFactors[0] > MAX_BIPS,
  liquidationFactors[2] > liquidationFactors[1] > MAX_BIPS,
  …

  so all subsequent indices automatically satisfy > MAX_BIPS.

Recommendation

Refactor the function to perform the upper‑bound check once before the loop, then omit it inside:

 function validateLiquidationFactors(
     uint256[] memory liquidationFactors,
     uint256[] memory vaultCollateralFactors
 )
     internal pure
 {
     require(liquidationFactors.length == vaultCollateralFactors.length, "lengths not equal");
     require(liquidationFactors.length >= 1, "at least one factor required");

+    // Only the first factor needs an explicit > MAX_BIPS check;
+    // monotonicity ensures all others are larger.
     require(liquidationFactors[0] > SafePct.MAX_BIPS, "factor not above 1");

     for (uint256 i = 0; i < liquidationFactors.length; i++) {
-        require(liquidationFactors[i] > SafePct.MAX_BIPS, "factor not above 1");
         require(vaultCollateralFactors[i] <= liquidationFactors[i], "vault collateral factor higher than total");
         require(i == 0 || liquidationFactors[i] > liquidationFactors[i - 1], "factors not increasing");
     }
 }

Impact (Insight)

This change reduces the number of SLOADs and comparisons by one per loop iteration, lowering gas consumption for callers—particularly important when many factor pairs are validated. The semantic behavior remains identical, making this an easy, low‑risk optimization.

Proof of Concept

Proof of Concept

test:

        it("Optimized setLiquidationPaymentFactors", async () => {
            const tx = await assetManager.setLiquidationPaymentFactors([10001, 10002, 10003, 10004, 10005], [10001, 10002, 10003, 10004, 10005], { from: assetManagerController });
        });

Gas report for orginal and optimized function:

Orginal : 199,324

Optimized: 199,036